The purpose of this project was to initiate a trial of activated autologous dentritic cell immunotherapy for patients with incurable advanced stage non small cell lung cancer (NSCLC). This pilot trial was undertaken in patients with established advanced stage NSCLC, and involved reinfusion of activated autologous dendritic cells in an attempt to elicit a tumor-directed cytotoxic T-lymphocyte response. Recent investigation in this area of tumor immunology supported this approach as a potentially powerful cancer therapy alternative. Over the 12 month period of patient recruitment three patients with advanced stage NSCLC were recruited for study, which involved a maximum of 4 consecutive therapy cycles, at two week intervals. Each cycle involved pheresis of peripheral blood mononuclear cells from the subjects, from which dendritic cells were purified by density centrifugation then reinfused. There were no observed toxicities, although two of the three patients developed transient low-grade fever within 1 hour of dendritic cell reinfusion. The principle limitations in this trial were the declining performance status of two of the patients over the study period, and the finding that two of the three patients had very low to no detectable circulating dentritic cells as their clinical courses progressed. This finding of peripheral dentritic cell depletion is biologically and clinically important, and has important implications for this approach to cancer immune therapy.